Search for: All records

In this paper, we propose a Flexible processing-in-DRAM framework named FlexiDRAM that supports the efficient implementation of complex bulk bitwise operations. This framework is developed on top of a new reconfigurable in-DRAM accelerator that leverages the analog operation of DRAM sub-arrays and elevates it to implement XOR2-MAJ3 operations between operands stored in the same bit-line. FlexiDRAM first generates an efficient XOR-MAJ representation of the desired logic and then appropriately allocates DRAM rows to the operands to execute any in-DRAM computation. We develop ISA and software support required to compute in-DRAM operation. FlexiDRAM transforms current memory architecture to a massively parallel computational unit and can be leveraged to significantly reduce the latency and energy consumption of complex workloads. Our extensive circuit-to-architecture simulation results show that averaged across two well-known deep learning workloads, FlexiDRAM achieves ∼15× energy-saving and 13× speedup over the GPU outperforming recent processing-in-DRAM platforms. 

This work investigates the role of extra oxygen vacancies, introduced by a hydrogen plasma at midpoint of deposition of a 6 nm thick HfO2 to reduce the switching power consumption in a RRAM device. Initially TiN, which is a commonly used metal in CMOS technology, was used as the top electrode for treated HfO2. Subsequently Ru and TaN as top electrodes were explored to enhance the switching behavior and power consumption. A range of compliance currents from 1 nA to 1 µA were used to evaluate the switching characteristics. The role of both TaN and Ru as bottom metal was also evaluated. With Ru as top metal the device switched at a compliance current of 1 nA and higher. Whereas when Ru was used as bottom electrode, devices were unable to switch below a compliance current of 50 µA. For TaN as top metal electrode, devices switched at and above 1 µA CC whereas with TaN as bottom metal the initial switching was at CC of 2 µA. It was observed that use of Ru as a top metal significantly reduced the switching energy of the plasma treated HfO2 RRAM device but was ineffective when used as a bottom metal.